U.S. patent application number 13/723555 was filed with the patent office on 2013-07-04 for localized surface plasmon resonance sensor using chalcogenide materials and method for manufacturing the same.
This patent application is currently assigned to KOREA INSTITUTE OF SCIENCE AND TECHNOLOGY. The applicant listed for this patent is KOREA INSTITUTE OF SCIENCE AND TECHNOLOGY. Invention is credited to Byung Ki CHEONG, Doo Seok JEONG, In Ho KIM, Won Mok KIM, Kyeong Seok LEE, Taek Sung LEE, Wook Seong LEE.
Application Number | 20130168789 13/723555 |
Document ID | / |
Family ID | 48694166 |
Filed Date | 2013-07-04 |
United States Patent
Application |
20130168789 |
Kind Code |
A1 |
LEE; Taek Sung ; et
al. |
July 4, 2013 |
LOCALIZED SURFACE PLASMON RESONANCE SENSOR USING CHALCOGENIDE
MATERIALS AND METHOD FOR MANUFACTURING THE SAME
Abstract
A localized surface plasmon resonance sensor may include a
localized surface plasmon excitation layer including a chalcogenide
material. The chalcogenide material may include: a first material
including at least one of selenium (Se) and tellurium (Te); and a
second material including at least one of germanium (Ge) and
antimony (Sb). The localized surface plasmon excitation layer may
be prepared by forming a thin film including the chalcogenide
material and crystallizing the thin film to have a predetermined
pattern by irradiating laser on the thin film.
Inventors: |
LEE; Taek Sung; (Seoul,
KR) ; LEE; Kyeong Seok; (Seoul, KR) ; KIM; In
Ho; (Seoul, KR) ; LEE; Wook Seong; (Seoul,
KR) ; JEONG; Doo Seok; (Gangwon-do, KR) ; KIM;
Won Mok; (Seoul, KR) ; CHEONG; Byung Ki;
(Seoul, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KOREA INSTITUTE OF SCIENCE AND TECHNOLOGY; |
Seoul |
|
KR |
|
|
Assignee: |
KOREA INSTITUTE OF SCIENCE AND
TECHNOLOGY
Seoul
KR
|
Family ID: |
48694166 |
Appl. No.: |
13/723555 |
Filed: |
December 21, 2012 |
Current U.S.
Class: |
257/431 ;
438/95 |
Current CPC
Class: |
H01L 31/0324 20130101;
H01L 31/186 20130101; G01N 33/54373 20130101; H01L 31/18 20130101;
B82Y 15/00 20130101; G01N 21/554 20130101; G02B 5/008 20130101 |
Class at
Publication: |
257/431 ;
438/95 |
International
Class: |
H01L 31/032 20060101
H01L031/032; H01L 31/18 20060101 H01L031/18 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 28, 2011 |
KR |
10-2011-0144676 |
Claims
1. A localized surface plasmon resonance sensor comprising: a
localized surface plasmon excitation layer comprising a
chalcogenide material, wherein the chalcogenide material comprises:
a first material comprising at least one of selenium (Se) and
tellurium (Te); and a second material comprising at least one of
germanium (Ge) and antimony (Sb).
2. The localized surface plasmon resonance sensor according to
claim 1, wherein carrier density of the localized surface plasmon
excitation layer is determined by the composition of the
chalcogenide material.
3. The localized surface plasmon resonance sensor according to
claim 1, wherein the chalcogenide material is crystalline.
4. The localized surface plasmon resonance sensor according to
claim 1, wherein the localized surface plasmon excitation layer
generates localized surface plasmons as being excited by infrared
light.
5. A method for manufacturing a localized surface plasmon resonance
sensor, comprising: forming a thin film comprising a chalcogenide
material comprising a first material comprising at least one of
selenium (Se) and tellurium (Te) and a second material comprising
at least one of germanium (Ge) and antimony (Sb); and forming a
localized surface plasmon excitation layer having a predetermined
pattern by irradiating laser on the thin film.
6. The method for manufacturing a localized surface plasmon
resonance sensor according to claim 5, wherein the thin film is
amorphous state and said forming the localized surface plasmon
excitation layer comprises crystallizing the chalcogenide material
with laser.
7. The method for manufacturing a localized surface plasmon
resonance sensor according to claim 6, wherein said crystallizing
the chalcogenide material with laser comprises changing the
irradiation location of laser according to the predetermined
pattern.
8. The method for manufacturing a localized surface plasmon
resonance sensor according to claim 7, wherein said crystallizing
the chalcogenide material with laser comprises adjusting one or
more of the intensity of laser, the moving speed of laser and the
pulse length of laser.
9. The method for manufacturing a localized surface plasmon
resonance sensor according to claim 6, wherein said crystallizing
the chalcogenide material with laser comprises irradiating a
plurality of coherent laser beams to the thin film.
10. The method for manufacturing a localized surface plasmon
resonance sensor according to claim 9, wherein the predetermined
pattern corresponds to an interference pattern formed by the
plurality of coherent laser beams.
11. The method for manufacturing a localized surface plasmon
resonance sensor according to claim 6, wherein said forming the
localized surface plasmon excitation layer further comprises
removing a laser-unirradiated region from the thin film.
12. The method for manufacturing a localized surface plasmon
resonance sensor according to claim 5, wherein said forming the
thin film comprises forming the thin film by sputtering.
13. The method for manufacturing a localized surface plasmon
resonance sensor according to claim 5, wherein said forming the
thin film comprises controlling carrier density of the thin film by
adjusting the composition of the chalcogenide material.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to Korean Patent
Application No. 10-2011-0144676, filed on Dec. 28, 2011, and all
the benefits accruing therefrom under 35 U.S.C. .sctn.119, the
contents of which in its entirety are herein incorporated by
reference.
BACKGROUND
[0002] 1. Field
[0003] Embodiments relate to s localized surface plasmon resonance
sensor using a chalcogenide material and a method for manufacturing
same.
[0004] 2. Description of the Related Art
[0005] Localized surface plasmon resonance is a phenomenon
occurring when a collective oscillation of free electrons in a
material is restricted inside a structure whose dimension is
smaller than the wavelength of incident light. Since the resonance
wavelength at which localized surface plasmons resonance is induced
is very sensitively dependent on particle size and shape, change in
surrounding medium, or the like, a biochemical sensor that can be
utilized in the field of medicine, environment, etc. may be
embodied using localized surface plasmon resonance. For example,
Korean Patent Publication No. 10-2011-0042848 discloses an optical
biosensor based on localized surface plasmon resonance.
[0006] As described in Korean Patent Publication No.
10-2011-0042848, precious metals such as gold (Au), silver (Ag) and
copper (Cu) are frequently used to induce localized surface plasmon
resonance. However, since the resonance wavelength of the localized
surface plasmon resonance is usually in the visible region when
such precious metals are used, only the change in the surrounding
medium sensitive to light in the visible region can be
detected.
[0007] The air coming out of the human lungs contain various
biomarkers allowing diagnosis of diseases of individuals. But,
since the wavelength allowing detection of the biomarkers is
usually in the mid-infrared region, there is difficulty in
detecting the biomarkers with the existing localized surface
plasmon resonance sensors using precious metals.
[0008] To overcome this problem, efforts are made to broaden the
resonance wavelength range by modifying the structure of the
precious metal materials. However, the modification of the
structure of the precious metal materials is not easy and it is
much more favorable to choose other materials that operate well in
the infrared region in terms of cost. Such materials may be
semiconductor materials that exhibit properties comparable to those
of metals in the infrared region although the density of electrons
or carriers is smaller than that of the precious metals. For this
reason, studies are carried out to change the resonance wavelength
using doped semiconductor material. But, the doping process is
complicated.
[0009] Meanwhile, it is of great importance to process a source
material to have precise patterns in order to obtain resonance
signals at wanted wavelength region using the localized surface
plasmon resonance sensor. For this, electron beam (e-beam)
lithography is employed for nanostructures and photolithography is
employed for larger structures.
[0010] However, since these top-down processes are complicated and
expensive, they are not suited for applications where a lot of
inexpensive sensors are required such as biological or ecological
detection. Although bottom-up type self-assembling processes are
attempted to overcome this problem, it is difficult to obtain the
desired patterns accurately.
REFERENCES OF THE RELATED ART
Patent Documents
[0011] (Patent document 1) Korean Patent Publication No.
10-2011-0042848
SUMMARY
[0012] In an aspect of the present disclosure, a localized surface
plasmon resonance (LSPR) sensor wherein a chalcogenide material is
used in an LSPR excitation layer and carrier density may be changed
variously depending on the composition of the chalcogenide material
may be provided.
[0013] In another aspect of the present disclosure, a method for
manufacturing an LSPR sensor whereby an LSPR excitation layer may
be patterned easily to have a desired structure using laser without
resorting to the complicated and expensive lithography process may
be provided.
[0014] A localized surface plasmon resonance sensor according to an
exemplary embodiment may include a localized surface plasmon
excitation layer including a chalcogenide material. The
chalcogenide material may include: a first material including at
least one of selenium (Se) and tellurium (Te); and a second
material including at least one of germanium (Ge) and antimony
(Sb).
[0015] A method for manufacturing a localized surface plasmon
resonance sensor according to an exemplary embodiment may include:
forming a thin film including a chalcogenide material comprising a
first material including at least one of selenium (Se) and
tellurium (Te) and a second material including at least one of
germanium (Ge) and antimony (Sb); and forming a localized surface
plasmon excitation layer having a predetermined pattern by
irradiating laser on the thin film.
[0016] According to the present disclosure, carrier density of the
LSPR excitation layer may be changed variously by controlling the
composition of the chalcogenide material constituting the LSPR
excitation layer and an LSPR sensor that may operate in the
infrared region may be provided. The LSPR excitation layer may be
formed to have a desired structure via simple direct writing using
laser without resorting to the complicated and expensive
lithography process.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The above and other aspects, features and advantages of the
disclosed exemplary embodiments will be more apparent from the
following detailed description taken in conjunction with the
accompanying drawings in which:
[0018] FIG. 1 shows extinction efficiency spectra of a localized
surface plasmon resonance sensor according to an exemplary
embodiment; and
[0019] FIG. 2 schematically illustrates a method for manufacturing
a localized surface plasmon resonance sensor according to an
exemplary embodiment.
DETAILED DESCRIPTION
[0020] Hereinafter, embodiments of the present disclosure will be
described in detail referring to the attached drawings.
[0021] A localized surface plasmon resonance (LSPR) sensor
according to an exemplary embodiment may comprise a light source,
an LSPR excitation layer and a detector. The light source may
irradiate light to the LSPR excitation layer. The LSPR excitation
layer generates localized surface plasmons as being excited by
incident light of a specific resonance wavelength. As a result, at
the resonance wavelength, most of light energy is transferred to
free electrons in the LSPR excitation layer. The detector may
detect a light absorption signal and/or a light scattering signal
by detecting light penetrating the LSPR excitation layer or
reflected on the LSPR excitation layer.
[0022] The LSPR phenomenon is characterized by light absorption
associated with the resonance and light scattering associated with
energy relaxation. Accordingly, the characteristics of the LSPR
resonance may be determined by recording the light absorption
signal and/or the light scattering signal as spectrum and analyzing
the wavelength of the spectral peaks and the intensity of the
peaks. Since the resonance wavelength at which LSPR occurs is very
sensitively dependent on the change in medium surrounding the LSPR
excitation layer, presence and/or state of the medium surrounding
the LSPR excitation layer may be detected using the signal detected
by the detector.
[0023] In an exemplary embodiment, the light source may irradiate
infrared light to the LSPR excitation layer as incident light. The
air coming out of the human lungs contain various biomarkers
allowing diagnosis of diseases. The wavelength allowing detection
of the biomarkers is usually in the mid-infrared region. Some
exemplary biomarkers, diseases corresponding to the biomarkers and
detection wavelength thereof are described in Table 1. The
detection wavelength of carbon dioxide given in Table 1 may be used
as a reference wavelength for detection of other biomarkers.
TABLE-US-00001 TABLE 1 Detection Biomarkers Diseases wavelength
(.mu.m) Acetone (OC(CH.sub.3).sub.2) Lung cancer, diabetes, 0.266
dietary fat loss, congestive heart failure Acetaldehyde
(CH.sub.3CHO) Alcoholism, liver 5.97 disease, lung cancer Ammonia
(NH.sub.3) Kidney disease, asthma 9-10.7, 10.0, 11.0, 10.3, 1.5
Carbon monoxide (CO) Oxidative stress, 1.6, 4.6, 4.88 respiratory
infection, anemia Carbon dioxide (CO.sub.2) Oxidative stress 4.23
(.sup.13C-isotope) Carbon dioxide (CO.sub.2) 1.6, 1.59, 4.9, 4.8,
5.2 Carbonyl sulfide (OCS) Liver disease 4.86, 4.9 Ethane
(C.sub.2H.sub.6) Infantile vitamin E 3.4, 3.0 deficiency, lipid
peroxidation, oxidative stress Ethylene (C.sub.2H.sub.4) Lipid
peroxidation, 10.5 UV-induced skin damage Methane (CH.sub.4) Bowel
disorder, 3.35 colonic fermentation Nitrogen monoxide (NO) Asthma,
bronchiectasis, 5.2 hypertension, rhinitis, lung disease
[0024] As seen from Table 1, the detection wavelength of many
biomarkers is in the infrared region. Accordingly, the light source
may be configured to irradiate infrared light. For example, it may
be configured to irradiate light in the wavelength region including
the detection wavelength of one or more specific biomarker(s). If
the LSPR excitation layer of the LSPR sensor comprises a material
excited by the infrared light, the LSPR sensor may be used as a
biochemical sensor for detecting biomarker(s) and may be utilized
variously in the field of medicine, environment, etc.
[0025] The LSPR excitation layer of an LSPR sensor according to an
exemplary embodiment may comprise a chalcogenide material. The
chalcogenide material may comprise a first material comprising
selenium (Se) and/or tellurium (Te) and a second material
comprising germanium (Ge) and/or antimony (Sb). For example, the
LSPR excitation layer may comprise a chalcogenide material wherein
germanium (Ge), antimony (Sb) and tellurium (Te) are mixed at
specific proportion. And, the chalcogenide material may further
comprise one or more additive(s) other than the above-described
materials.
[0026] It is known that the LSPR resonance wavelength is dependent
on the density of carriers (i.e., electrons or holes) in the LSPR
excitation layer. Accordingly, the LSPR resonance wavelength may be
shifted to the infrared region by adjusting the carrier density of
the LSPR excitation layer. In an exemplary embodiment, the carrier
density of the LSPR excitation layer comprising the chalcogenide
material may be controlled by adjusting the proportion of the
elements constituting the chalcogenide material. That is to say,
the composition of the chalcogenide material may be determined such
that the LSPR resonance wavelength lies in the infrared region.
[0027] For example, the inventors of the present disclosure have
found out that the carrier density and mobility of the LSPR
excitation layer comprising germanium (Ge), antimony (Sb) and
tellurium (Te) change as described in Table 2 as the proportion of
the elements is varied.
TABLE-US-00002 TABLE 2 Ge:Sb:Te Carrier density
(.times.10.sup.20/cm.sup.3) Mobility (cm.sup.2/Vs) 14:29:57 1.81
23.90 0:81:19 6.45 14.69 8:60:32 9.71 6.43 5:78:17 14.00 15.11
13:71:16 18.90 10.46 5:71:23 24.10 10.49
[0028] And, Table 3 shows the optical properties of the LSPR
excitation layer comprising germanium (Ge), antimony (Sb) and
tellurium (Te) depending on the proportion of the elements.
TABLE-US-00003 TABLE 3 Ge:Sb:Te .epsilon..sub..infin. .tau.
(10.sup.-15 s) .sigma..sub.dc (.OMEGA. cm).sup.-1 .omega..sub.p
(10.sup.14 rad/s) 50:0:50 57.1 2.78 3121 4.71 22:22:56 60.6 5.29
2230 2.80 14:29:57 51.7 5.23 1637 2.61 8:34:58 52.6 5.27 2754
3.35
[0029] In Table 3, .di-elect cons..sub..infin., .tau.,
.sigma..sub.dc and .omega..sub.p are optical parameters of the LSPR
excitation layer at the given proportion of germanium (Ge),
antimony (Sb) and tellurium (Te). .di-elect cons..sub..infin. is
the dielectric constant when the frequency of a signal is infinite,
.tau. is the relaxation time, .sigma..sub.dc is the conductivity
for a DC electrical signal and .omega..sub.p is the plasma
frequency.
[0030] The LSPR resonance wavelength of the LSPR excitation layer
is determined by the above-described optical parameters and the
extinction efficiency of the LSPR excitation layer may be
calculated from the optical parameters based on the Drude model. A
detailed description about the computation will be omitted since it
can be easily understood by those skilled in the art.
[0031] FIG. 1 shows extinction efficiency calculated for the LSPR
excitation layers having the composition described in Table 3.
[0032] Referring to FIG. 1, the four curves 201, 202, 203 and 204
respectively correspond to the LSPR excitation layers having the
composition described in Table 3. That is to say, the curve 201
represents the extinction efficiency of the LSPR excitation layer
whose Ge:Sb:Te ratio is 50:0:50, the curve 202 represents the
extinction efficiency of the LSPR excitation layer whose Ge:Sb:Te
ratio is 22:22:56, the curve 203 represents the extinction
efficiency of the LSPR excitation layer whose Ge:Sb:Te ratio is
14:29:57 and the curve 204 represents the extinction efficiency of
the LSPR excitation layer whose Ge:Sb:Te ratio is 8:34:58.
[0033] When LSPR occurs, light absorption and/or scattering by the
LSPR excitation layer increases, and, this leads to increased
extinction efficiency. Accordingly the wavelengths at which the
peaks are observed in the curves 201, 202, 203 and 204 of FIG. 1
correspond to LSPR resonance wavelengths. That is to say, the LSPR
resonance wavelength for the curve 201 is about 4.05 .mu.m, the
LSPR resonance wavelength for the curve 202 is about 5.71 .mu.m,
the LSPR resonance wavelength for the curve 203 is about 6.75 .mu.m
and the LSPR resonance wavelength for the curve 204 is about 7.32
.mu.m. Since the LSPR resonance wavelength lies in the
near-infrared, mid-infrared and far-infrared regions, an LSPR-based
infrared sensor may be manufactured using the LSPR excitation layer
having the composition described in Table 3.
[0034] The carrier density of the LSPR excitation layer of the LSPR
sensor may be controlled by adjusting the composition of the LSPR
excitation layer comprising the chalcogenide material and the LSPR
sensor may operate in the infrared region. Whereas the existing
LSPR sensor uses doped semiconductor material to extend the
wavelength region, the LSPR sensor according to the present
disclosure required no doping and the LSPR resonance wavelength may
be easily controlled by variously adjusting carrier density through
control of the proportion of the elements in the chalcogenide
material.
[0035] Hereinafter, a method for manufacturing an LSPR sensor
comprising an LSPR excitation layer comprising a chalcogenide
material according to an exemplary embodiment will be
described.
[0036] In an exemplary embodiment, an LSPR excitation layer
comprises a chalcogenide material whose phase changes by heat
treatment. The chalcogenide material is amorphous phase in the
as-deposited state and has nonmetallic, i.e. dielectric-like,
property in the infrared region. But, after heat treatment, the
chalcogenide material is converted to crystalline and exhibits
metallic property. Accordingly, an LSPR excitation layer comprising
a crystalline chalcogenide material may be formed by direct laser
writing.
[0037] FIG. 2 schematically illustrates a method for manufacturing
a localized surface plasmon resonance sensor according to an
exemplary embodiment.
[0038] Referring to FIG. 2, a thin film 40 comprising a
chalcogenide material may be formed on a substrate 30. The
substrate 30 serves as a space for forming an LSPR excitation layer
and may comprise a dielectric material although not being limited
thereto. The substrate 30 may be either included as a part of the
finally manufactured LSPR sensor or may be removed or separated
from the LSPR sensor. The thin film 40 may be formed by sputtering
or other adequate method and is amorphous pahse in the as-formed
state.
[0039] Those skilled in the art will easily understand that the
substrate 30, the thin film 40, etc. illustrated in FIG. 2 are
given only as an example to describe the process of manufacturing
the LSPR excitation layer and their actual locations, sizes or
shapes may be different.
[0040] After the thin film 40 is formed, the thin film 40 may be
crystallized by irradiating laser. For example, a laser beam may be
irradiated using a light source 10 and the laser beam may be
converged on the thin film 40 using a prism 20. Since the thin film
40 comprises the chalcogenide material whose phase is changeable,
irradiation of laser of an adequate intensity to the thin film 40
may result in crystallization of the laser-irradiated region owing
to heat. The LSPR excitation layer may be formed by crystallizing
the thin film 40 to have a predetermined pattern in this manner.
The crystallized pattern may be a 3-dimensional structure pattern
capable of generating LSPR. For example, the 3-dimensional
structure may be a nanostructure such as a nanodisc, a nanorod,
etc., but is not limited thereto.
[0041] In an exemplary embodiment, to crystallize the thin film 40
to have the 3-dimensional structure, the laser may be irradiated
while changing the irradiation location of laser on the thin film
40. For example, the irradiation location of laser on the thin film
40 may be changed by moving the thin film 40 with the light source
10 fixed or by moving the light source 10 with the thin film 40
fixed. Also, the size and shape of the crystallized region of the
thin film 40 may be controlled by the intensity of laser, the
moving speed of laser, the pulse length of laser, or the like.
[0042] Instead of crystallizing the thin film by directly
irradiating laser according to the pattern shape, the pattern may
be formed by irradiating a plurality of coherent laser beams in
another exemplary embodiment. The plurality of coherent laser beams
may be irradiated to the thin film 40 such that an interference
pattern is formed by the laser beams. In this case, an array
structure may be formed by adjusting the crystallizing region
according to the intensity of laser using the difference in
constructive interference and destructive interference of the
interference pattern. For example, the size and shape of the
crystallized region of the thin film 40 may be determined according
to the interference pattern by adjusting, for example, the
intensity of the coherent laser beams such that the thin film 40 is
crystallized at the region corresponding to the constructive
interference and the thin film 40 is not crystallized at the region
corresponding to the destructive interference.
[0043] A laser-unirradiated region of the thin film 40, which
remains amorphous state, may be removed. As a result, only the
crystallized region may remain to form the LSPR excitation layer.
For example, after the thin film 40 is crystallized according to
the predetermined pattern, selective wet etching may be carried out
using a tetramethylammonium hydroxide (TMAH) solution. By adjusting
the concentration of the TMAH solution, only the amorphous region
may be selectively removed from the thin film 40 except for the
crystallized region. For example, selective wet etching may be
carried out using a TMAH solution with a concentration of about
25%.
[0044] Thus formed LSPR excitation layer may be assembled with a
light source and a detector to manufacture an LSPR sensor.
According to the method for manufacturing an LSPR sensor described
above, a desired structure may be prepared easily by direct laser
writing without resorting to the costly lithography process.
[0045] While the exemplary embodiments have been shown and
described, it will be understood by those skilled in the art that
various changes in form and details may be made thereto without
departing from the spirit and scope of the present disclosure as
defined by the appended claims. In addition, many modifications can
be made to adapt a particular situation or material to the
teachings of the present disclosure without departing from the
essential scope thereof. Therefore, it is intended that the present
disclosure not be limited to the particular exemplary embodiments
disclosed as the best mode contemplated for carrying out the
present disclosure, but that the present disclosure will include
all embodiments falling within the scope of the appended
claims.
* * * * *